(Russian, petrofizika), science of the geologic cycle dealing with the relationship between the physical properties of rocks and the rocks’ mineral composition, structure, and history of formation. Petrophysics developed on the basis of geophysical research and is closely associated with solid-state physics, experimental petrography and mineralogy, engineering geology, tectonics, and the theory of minerals. The concept of petrophysics was introduced by the geophysicist F. Frölich of the German Democratic Republic in 1953. Petrophysics involves the study of the properties of rocks en masse through geological field methods, geophysical and cosmophysical research, and laboratory research methods (determination of physical parameters with subsequent petrographic study and mathematical analysis of the materials). The material obtained from field research is classified according to properties, and the results of the study of the rock properties are presented in the form of petrophysical maps and profiles—petrovelocity, petromagnetic, petrodensity, or other types of maps providing the petrophysical characteristics of individual regions are compiled for the parameters being determined. Study of the effect of the composition and structure of rocks on the physical properties has permitted the development of methods for calculating the elastic parameters of rocks as a function of mineral composition. Much attention is given to rock anisotropy, which is closely connected with the properties of rock-forming minerals and the texture of rocks. Petrophysics uses data on the physical properties of certain rocks to establish the specific thermodynamic conditions of the rocks’ formation, thus making possible physicomechanical modeling for the study of the properties of rocks under high pressure and temperature. Such modeling was begun in the 1950’s in the USA by O. Anderson, F. Birch, G. Simmons, and others. It is being carried on in the 1970’s in the USSR by G. D. Afanas’ev, M. P. Volarovich,

Iu. V. Riznichenko, S. I. Subbotin, and others, in Czechoslovakia by Z. Pros, V. Babuŝka, and V. Hanuŝ, in the German Democratic Republic by H. Stiller and H. Militzer, in Japan by S. Matsushima and others, in India by S. Balakrishna, and in Australia by R. Liebermann.

Petrophysics has gained particular importance in the 1960’s and 1970’s because of the need for studying the deep mantle of the earth’s crust in order to elucidate the sources of ore matter, the genesis of rocks, and seismic phenomena.